Renewable and sustainable strategies for improving the thermal environment of Chinese solar greenhouses

Chinese solar greenhouses (CSGs) play an important role in horticultural development, providing high-efficiency thermal storage performance compared to the other greenhouse styles. CGSs are fully passive solar greenhouses for vegetables without auxiliary heating system during the winter. To improve the thermal environmental conditions of CSGs and produce better crops, some strategies have been investigated to improve the thermal environments. In this study, a comprehensive review is presented focusing on key strategies for improving the thermal environment in CSGs. The technologies considered within the scope of this research are mainly renewable and sustainable solutions such as structures (sunken CSG, variable south roof CSG, air channel heat exchange CSG), options for north wall materials (hollow wall, pebble wall, phase-change materials), and equipment for thermal storage (water circulation thermal storage, energy-efficient heat pump thermal storage, photovoltaic thermal storage). These new findings revealed that through the application of a single strategy or synergistic strategies, we can maximize the utilization of renewable and sustainable energy to provide indoor heating. This review also provides a reference for design, application and research on thermal storage and energy-saving strategies for CSGs. (c) 2019 Elsevier B.V. All rights reserved.